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September 23, 2019

Dear Parents/Guardians,

A case of Eastern Equine Encephalitis (EEE) has recently been diagnosed in a horse in Montcalm County. This is the first case of EEE in a horse in Montcalm County since 2005 and the fifth since 1942.  To date, no case of human EEE has ever been found in Montcalm County since this disease was first tracked in humans in 1980. No human or animal cases have been reported in Isabella County, Gratiot Counties, or any other surrounding counties. At this time, it is felt that the risk of EEE in humans in Gratiot County and Isabella County is VERY LOW and we do not feel it is necessary to reschedule or change outdoor sports schedules. However, avoiding mosquito bites is still, and always is, advised as they could still transmit this disease as well as other, such as West Nile Virus.

One way to avoid mosquito bites is to avoid outdoor activities occurring at or after dusk, when mosquitos are at their worse. There are many other ways to avoid mosquito bites including:

  • Apply insect repellents that contain the active ingredient DEET, or other U.S. Environmental Protection Agency-approved product to exposed skin or clothing, and always follow the
    manufacturer’s directions for use.
  • Wear long-sleeved shirts and long pants when outdoors. Apply insect repellent to clothing to help prevent bites. Permethrin is a particularly effective repellant for clothing and equipment.
  • Maintain window and door screening to help keep mosquitoes outside.
  • Empty water from mosquito breeding sites around the home, such as buckets, unused kiddie pools, old tires or similar sites where mosquitoes may lay eggs.
  • Area spraying is NOT generally effective this late in the year and in general is not recommended.

EEE is a disease maintained in birds, and spread between birds by mosquitos. Certain species of mosquitos can also spread it from birds to some mammals, such as horses, deer, and humans. It cannot be passed between mammals, such as from horse to humans. However, cases in horses are a sign there is EEE in the area.

EEE infection in humans is one of the most dangerous mosquito-borne diseases in the United States and there have now been 8 human cases confirmed in Michigan. People aged over 50 years and under 15 years are at increased risk for serious disease. Since 1980, there have been no more than 1 to 3 human cases identified in Michigan each year, primarily in southern and southwestern Michigan. For more information, go to and

Jennifer Morse, MD, MPH, FAAFP
Medical Director